/*-------------------------------------------------------------------*/
/* testitimer.c                                                      */
/* The setitimer system call.                                        */
/*-------------------------------------------------------------------*/

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <signal.h>
#include <sys/time.h>

/*-------------------------------------------------------------------*/

static void mySignalHandler(int iSignal)

/* This function is intended to be a handler for signals of various
   types.  Print iSignal to stdout, and then re-register this function 
   as the handler for signals of type iSignal. */

{
   void (*pfRet)(int); 
   printf("In mySignalHandler with argument %d\n", iSignal);
   pfRet = signal(iSignal, mySignalHandler);
   assert(pfRet != SIG_ERR);
}

/*-------------------------------------------------------------------*/

int main(int argc, char *argv[])

/* Illustrate the setitimer system call. */

{
   int iRet;
   void (*pfRet)(int); 
   struct itimerval sTimerValue;
   struct itimerval sOldTimerValue;

   pfRet = signal(SIGPROF, mySignalHandler);
   assert(pfRet != SIG_ERR);

   /* Create an interval timer to generate a SIGPROF signal after 
      A seconds and B microseconds of virtual time.  Thereafter 
      repeatedly generate a SIGPROF signal at C second, D microsecond
      intervals of virtual time. */
   sTimerValue.it_value.tv_sec = 1;      /* A */
   sTimerValue.it_value.tv_usec = 0;     /* B */
   sTimerValue.it_interval.tv_sec = 1;   /* C */
   sTimerValue.it_interval.tv_usec = 0;  /* D */
   iRet = setitimer(ITIMER_PROF, &sTimerValue, &sOldTimerValue);
   assert(iRet != -1);

   printf("Entering an infinite loop\n");
   for (;;)
      ;

   return 0;
}


/* Sample execution:

$ gcc -Wall -ansi -pedantic -o testitimer testitimer.c
$ testitimer
Entering an infinite loop
In mySignalHandler with argument 27
In mySignalHandler with argument 27
In mySignalHandler with argument 27
In mySignalHandler with argument 27
In mySignalHandler with argument 27
In mySignalHandler with argument 27
^C

*/